/* Rubik's torus widget, adapted from torus_app/index.html (see rubik-torus.js).
   Everything is scoped to .rt, in the light theme of the page. */
#rubik-torus {
  margin-top: 3rem;
}

.rt {
  --rt-bg: hsl(210, 20%, 98%);          /* page background (latex.css) */
  --rt-fg: #161a20;
  --rt-muted: #59616c;
  --rt-line: #ccd2d9;
  --rt-btn: #ffffff;
  --rt-btn-hover: #edf0f3;
  --rt-accent: #a8203a;
  --rt-accent-soft: rgba(168, 32, 58, 0.09);
  --rt-plastic: #3a3e44;                /* the lines between the tiles */
  --rt-veil: rgba(247, 249, 250, 0.66);
  --rt-frame: hsl(210, 20%, 98%);       /* same as the page background (--rt-bg) */
  max-width: 400px;
  margin: 1rem auto 0;
  color: var(--rt-fg);
  line-height: 1.45;
  -webkit-tap-highlight-color: transparent;
}

.rt button {
  font: inherit;
  color: inherit;
}

.rt button:focus-visible {
  outline: 2px solid var(--rt-accent);
  outline-offset: 2px;
}

/* options: grid size and turn direction */
.rt-options {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 8px 16px;
}

.rt-seg {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

/* The label hangs to the left, so that the buttons alone are centered. It is
   in the same font, size and color as the text of the buttons. */
.rt-seg-k {
  position: absolute;
  right: 100%;
  margin-right: 10px;
  white-space: nowrap;
  font: inherit;
  color: var(--rt-fg);
}

/* buttons: the options above the board and the actions below it, all in
   the page font (see .rt button) */
.rt-act,
.rt-seg button {
  height: 2.25rem;
  padding: 0 14px;
  border: 1px solid var(--rt-line);
  background: var(--rt-btn);
  border-radius: 0;
  cursor: pointer;
  touch-action: manipulation;
}

.rt-seg button {
  min-width: 2.25rem;
  padding: 0 10px;
  font-variant-numeric: tabular-nums;
}

.rt-act:hover,
.rt-seg button:hover {
  background: var(--rt-btn-hover);
}

.rt-act:active,
.rt-seg button:active {
  transform: translateY(1px);
}

.rt-seg button[aria-checked="true"] {
  color: var(--rt-accent);
  background: var(--rt-accent-soft);
  border-color: var(--rt-accent);
}

.rt-seg button svg {
  display: block;
  width: 16px;
  height: 16px;
  margin: 0 auto;
}

.rt-act:disabled {
  opacity: 0.45;
  cursor: default;
  transform: none;
}

.rt-act:disabled:hover {
  background: var(--rt-btn);
}

/* board */
.rt-stage {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  margin: 0.75rem auto 0;
}

.rt-board {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  display: block;
  /* Vertical swipes scroll the page; horizontal drags slide the torus. */
  touch-action: pan-y;
  cursor: pointer;
  border-radius: 8px;
}

.rt-board.sliding {
  cursor: grabbing;
}

.rt-board:focus {
  outline: none;
}

.rt-board:focus-visible {
  outline: 2px solid var(--rt-accent);
  outline-offset: 2px;
}

.rt-board.shuffle {
  animation: rt-shuffle 260ms ease-out;
}

@keyframes rt-shuffle {
  from { opacity: 0.25; transform: translate(-50%, -50%) scale(0.985); }
  to { opacity: 1; transform: translate(-50%, -50%) scale(1); }
}

/* actions */
.rt-actions {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin-top: 0.75rem;
}

@media (max-width: 720px) {
  .rt-actions .rt-act {
    flex: 1 1 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .rt-board.shuffle {
    animation: none;
  }
}